Printing plate and the process of making the same



June 11, 1935. J, MacLEAN 2,004,824

PRINTING PLATE AND THE PROCESS OF MAKING THE SAME v Filed March 9, 1951 Patented June 11, 1935 PRINTING PLATE AND THE PROCESS OF MAKING THE SAME John MacLean, Pueblo, 0010.

Application March 9, 1931, Serial No. 521,299

13 Claims.

My present invention relates to printing plates and the method of making the same, and particularly to plates and a method adapted to be used in connection with fiat rigid, curved rigid, or

flexible metal printing plates intended for use upon'platen or cylinder presses, rotary or offset presses, and in fact any other form of printing press, without pressing or carrying the impression through the sheet,'to thus give the effect and simulation of planographic, lithographic or offset work.

An object of this invention is to provide a plate and process that can be used to reproduce lithographic eifects, halftones, or any fine detail, and that will reproduce the printing matter efficiently and satisfactorily on rough or text papers, bond or linen-finished papers, cloth, wood, tissue papers, gummed paper, and in fact any smooth or rough surface as usually printed upon.

Another object is to provide a plate, of substantially planographic character, that can be quickly and inexpensively prepared to print any desired matter and that will effectively function to prevent smudging of the printed sheet, without the use of water or other solutions, or offsetting upon subsequently printed sheets. I

Still another object is to providea plate and method of producing the same by which the plate is effectively treated and mercurialized on nonprinting portions of the face thereof to resist ink and prevent smudging of thework, which mercurialized surface or portions will not readily break down when the press is stopped or the plate is otherwise temporarily out of use.

A still further object is to provide a plate having a body portion of a material having an affinity for mercury and yet resistant to complete amalgamation, and having desired printing portions on the face thereofdefined in a material readily taking ink and resistant to mercury.

With the above and other objects in view, which will be apparent to those skilled in the art, my invention includes certain novel features of construction and certain novel steps and proceedings in carrying out of the method,'which will be hereinafter more fullyset forth in connection with the drawing.

In the drawing:

Figure 1 is a view in perspective showing a plateconstructed in accordance with my invention and after the manner of mymethod.

Fig. 2 is a much enlarged fragmentary'sectional view through a plate to better show the invention. Fig. 3 is a face view of a slip sheet to apply pres- As my invention is illustrated in the present in- 10 stance, the plate I is shown mounted on a block or a backing 2, the plate being fiat; however, it is to be understood that my improvements are equally well suited for use upon curved plates and that theessential feature isthat the printing face be substantially smooth. Any form of backing or supporting structure might be substituted for the block 2. r The plate l is of German silver, or other suitable alloy metal or material having an ingredient such as nickel, not affected by mercury, and an ingredient, such as zinc, readily amalgamating with mercury. The plate has the desired printing portions defined on the face thereof in any suitable manner, as by photographic or transfer methods or by photomechanical or other process, and after suitable fixative steps the image will be burnt in or otherwise hardened. In the present illustration the desired printing portions are illustrated at 3, and where photographic processes are employed to define the printing portion exposure and fixation will result inan enamel coating over the printing portions of the plate hardened by light exposure and the burning in, while the remaining background portions of the plate will be presented as raw and uncoated German silver. This printing portion 4 presents a slight elevation above the surface of the plate, as at 4, but the plate is to all intents and purposes sub-- stantially a planograph plate, without sufficient recess to clear the inking roller and paper in the background portions. To overcome such printing and smudging, the metal of the plate on the background portions is cleaned and Washed in a nitrate silver solutionconsisting of one ounce of nitrate of silver and one-eighth ounce of R0- chelle salts dissolved in and mixed with thirtytwo ounces of distilled water. After this plate wash has been applied, mercury is rubbed or brushed on and the background portions, as at 5, take a coating of liquid mercury which is highly resistant to ink.

With the plate prepared in this manner, the printing portion 3 will take ink and resist mer-. cury and the mercury treatment on the back-- ground portion, as at 5, causes the plate to absorb the mercury and become completely mercurialized to resist ink. The plate thus prepared can be used in any form or type of printing press, and to give an even yielding pressure upon the sheet to be printed, it is desirable that the press be prepared somewhat after the manner illustrated in Figs. 3 and 4. The draw sheet I5 is so prepared that the pressure portion II thereof will cover the entire printing or image portion of the plate I but will avoid pressure as far as possible upon the background and edge portions of the plate, and in some instances it may be found desirable to round off the edges of the plate body, as illustrated in Fig. 4 so that there will be no tendency to emboss or recess the outline of the plate into the paper. Referring to Fig. 4, the backing sheet I2, which can beof cushion rubber or of rubber having a backing layer I3 of cork or other suitable material is cemented to or otherwise secured upon the impression sheet I3 andis cut to the desired shape, substantially as indicated at II in Fig.3, so that it will take any or all of the desired printing portion of the plate but will avoid the edges thereof. The draw sheet I5 is then placed to receive the paper in the usual manner, 'and thepress is ready for printing upon substantially any ordinary material, whether rough or smooth. It is perhaps desirable that lithographic inks or inks containing'a small quantity of oleic acid be used for printing.

If a long run is to be made, the mercury resist coating may become thin in parts, and if such occures, it is only necessary to again treat the background or non-printing portions with mercury and the plate is restored to its original condition. If the plate is to be stored it may be found desirable to coat the same with asphaltum liquid,

gum arabic solution, or some other readily removed material to exclude air.

'While the enamel or, other printing surface as herein described may work efficiently under some conditions, it is preferable that the plate I have 'the printing portions 3 thereon defined in more durable material, and with this in mind a preferred embodiment of my invention consists in applying a plate of nickel or chromium over the printing face of the German silver plate I. With the desired printing portions covered with nickel or chromium, resistant to mercury, the plate can be prepared in the manner set forth above and can be used as described.

In preparing plates with the nickel or chromium printing portions I have found that a relatively thin plating of nickel, chromium or other non-plating material applied upon the face of a German silver plate or body will be very durable, and this plate with the metal coating lends itself particularly well to preparation of a printing plate. In the preparation of the plate, the design is applied upon the nickel, chromium coating or.

other non-plating material, by using transfer paper or any other of the known methods, and the design thus obtained is dusted with a resist to acid, such asdragonsblood, after which the resist treated portion is heated to burn in the enamel.

The plate is then etched, as by the use of a solution of iron chloride, to eat through the coating and expose the German silver body on all parts except the desired printing portions, and when the enamel or other transfer matter is cleaned from the plate, the printing portions will be defined by the coating of nickel or chromium or other plating material resistant to mercury and the background or non-printing portions can be mercurialized in the manner set forth.

As illustrated in Fig. 2 a light coating of nickel or chromium permits etching through to the German silver body plate I without undercutting beneath the printing surface and the mercurialized filling at 5 is readily applied to adhere to the metal of the body 2.

In the modified showing in Fig. 5, the body I, or German silver is applied as a coating of thin layer upon any suitable metallic base 6 and the nickel or chromium or other non-plating material layer 8 is coated upon this coating of German silver. When the design is etched as at 9, the German silver is exposed and will take the mercury as indicated at I0. With this modified arrangement and method it may be possible to use base plates 6 of copper, iron, or any other metal that will accept and hold a coating or layer I of German silver, applied by plating or by mechanical methods onf'the face of the body 6.

As the nickel or chromium of the printing layer has much the'same appearance as the German silver of the body of the plate, it "may be found desirable to give a very light coating I6 'of copper or other material of contrasting color immediately below the nickel or chromium layer or coating 3, as shown in Fig. 6, so that in the etching step the operator can readily determine when the nickel or chromium is etched away and by continuing through this coating or layer of contrast ing material can be certain that the surface of the' German silver is exposed to form a proper, base for the mercurializing treatment.

Where the mercury is applied to the German silver body, on the background portions, the

nickel of the alloy seems to resist penetration of the mercury to form an amalgam underneath the material defining the printing portions, so that these portions will not be loosened to peel off or will not themselves become spotted through penetration of the mercury; and, at the same time, the

zinc seemingly amalgamates with the mercury in such a manner that the plate body is filled or' loaded with mercury after the manner of 'a res ervoir, thus containing more mercury 'and'presenting a more resistant background portion than would be possible with the use of a metal having only a surface affinity or surface coating to ac-' complish mercurializing. H

Where the plate having printing portionsdefined by the use of nickel, iron or chromium is to be stored, it is particularly desirable that the plate be treated with an air-excluding material,

sary to re-treat the same when the plate is again ready for use. r I While I have herein shown and describ'ed'only certain specific embodiments of my invention'and have suggested only certain possible 'modifica' tions, it will be appreciated that many other changes and variations can be made'without de-" parting from thespirit and scope of my'invention.-

I claim: 7 p i 1. A printingplate comprising a plate of'alloy material inherently having an amnityfor mercury in amalgamation and yet resistant to com. plete amalgamation and having printing areas on.

the face thereof substantially completely resistant to mercury.

2. A printing plate comprising a bodyof an alloy material inherently possessing properties to retain mercury in amalgamation and to resist complete amalgamation, said body having printing portions defined on the face thereof by material receptive to ink and resistant to mercury and having background portions treated with mercury to resist ink.

3. A printing plate comprising a body portion of an alloy having a surface affinity for mercury and including material resistant to complete amalgamation, said body portion having desired printing portions on the face thereof treated to receive ink and resist mercury and the remaining portions on the face being treated with mercury to resist ink.

4. A printing plate comprising a body portion of an alloy having an ingredient resistant to amalgamation and an ingredient subject to amalgamation, said body having desired printing portions defined on the face thereof by material resistant to mercury.

5. A printing plate of German silver provided with an ink receiving and mercury resisting treatment on desired printing portions of its face and having remaining portions of the face treated with mercury to resist ink.

6. A printing plate comprising a German silver body having a nickel coating on the desired printing portions of the face to take ink and having the remaining portions of the face treated with mercury to resist ink.

7. A printing plate comprising a body of an alloy including nickel, said body having desired printing portions on the face thereof nickel coated to take ink and resist amalgamation and having remaining portions of the face treated with mercury to resist ink.

8. A printing plate comprising a body portion of an alloy including nickel and an ingredient subject to amalgamation, said body having desired printing portions defined on the face thereof by material resistant to mercury and having remaining portions of the face treated with mercury.

9. A printing plate comprising a body portion of an alloy having as ingredients nickel in supporting quantities and zinc in amalgamatable quantities, said body having desired printing portions on the face thereof coated with nickel to resist amalgamation and having remaining portions treated with mercury to secure a mercur rialized background portion to risist ink.

10. The process of making a printing plate which comprises, taking a body portion of an alloy substantially homogeneous throughout and having an ingredient resistant to amalgamation and an ingredient subject to amalgamation, applying to the face thereof material resistant to mercury and receptive to ink, defining desired printing portions and removing the resistant material around said printing portions, and directly treating the portions of the face of the body thus exposed with mercury.

11. The process of making printing plates which comprises, taking a body portion of German silver, applying to desired printing portions on the face thereof material resistant to mercury and receptive to ink, and directly mercurializing the face of the body around said printing portions.

12. The process of making printing plates which comprises, taking a body portion of German silver, applying to the face thereof a layer of nickel, defining desired printing portions and removing the nickel around said printing portions to expose the body, and directly mercurializicng the body portion around said printing porions.

13. The process of making printing plates which comprises, taking a body portion of German silver, applying a layer of nickel on the face thereof, etching away the nickel coating in part to leave only desired printing portions defined by the remaining nickel coating, and directly treating the exposed portions of the German silver body with mercury.

JOHN MAcLEAN. 

